Software speeds up helicopter rotor calibration process

British engineers who used a 10-year-old mathematical research project to minimise vibrations in helicopter rotors have been recognised with an industry award.

Researchers from Bristol University and UK company Helitune, whose software is used to balance aircraft propellers to reduce vibrations, last week won best partnership at the Technology Strategy Board’s (TSB) Knowledge Transfer Awards for their collaboration to improve Helitune’s algorithms.

The software, based on a mathematical technique originally devised by Bristol’s Prof Nick Lieven, cuts down the number of test flights a helicopter must fly to calibrate its rotors by calculating several different measurements simultaneously and speeding up the adjustment process.

‘It’s a perfect example of where fundamental research, which had no application at the time, has fed into solving a very practical and difficult mathematical problem with direct relevance for industry,’ said Lieven, who is now Bristol’s pro-vice-chancellor.

When a helicopter’s rotor is first assembled, several test flights are needed to gradually balance them by repeatedly measuring a number of parameters — such as the angle of the blades and the distribution of weight across them — and calculating what adjustments need to be made.

‘The trick that we could that others couldn’t was solve all the different parameters simultaneously rather than do them one after the other,’ said Lieven. ‘Whereas before it could take eight or nine flights now you can do it in four or five.’

Helitune and Bristol University are now collaborating on several further TSB co-funded projects worth around £600,000, to apply the technique to other rotating machines including wind and other power-generating turbines.

‘It’s moved on because we now have a far better understanding of vibrations in machinery and how we can interrogate it. So we can now use that to predict when failures in machinery are about to occur [based on the vibrations].’ said Lieven.

He added: ‘The key to this was that we weren’t precious about intellectual property. The University of Bristol is never going to produce a helicopter, so letting industry use the outcome of a piece of fundamental research, which was originally paid for by the UK taxpayer, has been of benefit to UK industry.’